1. Field of the Invention
A rearview panoramic head-up display device for vehicles and, more particularly, to the rearview panoramic head-up display device for synthesizing a three-dimensional rearview image, to know the view image around the car without moving the line of sight through a large angle, to thereby improve traffic safety.
2. Brief Description of the Related Art
The driver may pay attention on the condition in front of the car anytime, and may also pay attention on the rear car. Therefore, an in-car rearview mirror is set above the windshield in the car for reflecting the rear image. However, the visual range of the rearview mirror is small, a left rearview mirror and a right rearview mirror are set on the front outside of the left and right front doors of the car respectively. The driver may use the three reflection mirrors to observe the image in rear of the car.
Since the distance between the in-car rearview mirror and the left and right rearview mirrors is so far that the driver cannot give consideration to the three mirrors within the forward aspect angle, the driver should timely raise his head to check the in-car rearview mirror in the interval of looking at the road in front of the car, check the left rearview mirror when turning left, and check the right rearview mirror when turning right. This kind of moving line of sight frequently may easily make the driver tired, and the driver is also difficult to perform the real rearview action usually. Moreover, there are blind spots of line of sight when using the two left and right rearview mirrors, thus the suggestion of traffic safety dogma is that the driver may turn his head to check the condition in rear of the car directly when turning or changing lanes, the driver cannot rely on the rearview mirrors completely. This makes driving harder that the traffic accidents happened frequently.
In order to solve the problem of the above blind spot of line of sight, the head-up display used in the aircraft is employed by the industries as a driving auxiliary equipment. Originally, pilots may conveniently obtain desired messages by using this kind of head-up display, which directly project messages in front of the cockpit to avoid pilots lowering head to check the messages on the instrument board, that pilots can easily combine the messages displayed by the head-up display with the outside scene. Since the image reflected into eyes and the central axis of the aircraft is balanced, the height of pilots may not cause error on pitch angles or visual aim. Therefore, the purpose of the head-up display is that pilots may always keep the head-up posture without lowering head to check the messages displayed on the instrument board, to reduce ignoring the rapid change in the external environment during the interval between lowering head and heading-up, and avoid the delay and discomfort due to eyes focal length is adjusted continuously. Thus, using this kind of head-up display to the vehicles may reduce the drivers' eyes load.
Otherwise, it is one of the biggest main reasons of car accidents that drivers' line of sight is away from the front road when driving. In order to reduce the frequency and duration that drivers' line of sight away from the front road, some car manufacturers equip this kind of head-up display inside the luxury cars, thus, the drivers know the information, such as car speed and engine speed, without moving line of sight away from the front windshield, to maintain traffic safety.
In general driving condition, the shortest time of moving the line of sight away from the front road for reading the information displayed on the instrument board is 0.5 second. For the condition of highway speed of 100 km per hour, the car travels 30 meters per second, and the risk is increased when there are a lot of cars on the road. For safety, the car manufacturers may equip the head-up display in some cars to reduce the distraction of drivers, and the head-up display is used as marking practices to attract consumers.
Recently, the technique of the head-up displays used in the cars is less complicated than the head-up displays equipped in aircrafts. It is one kind of optical system, and generally it is consisted of two main equipments, which are a projector and a combiner. The projector is consisted of signal light sources, projection lens and other optical components. The signal light source of the projector is consisted of LCD monitors or CRT equipments. Light is emitted from the signal light source and projected to the combiner on the glass (or a special transparent screen) by the projector, and the combiner displays words or images.
In the recent years, there are many head-up displays for installation in car in the market. These head-up displays may simply display car speed and engine speed, now display water temperature, throttle position, fuel, over-speed warning, reverse image, battery voltage, and even combine the speed radar. Some products are stressed as quick installation, which are just connected to the car PC without using other cables. In the luxury cars of some car manufacturers, the information of the navigation system, front and rear vehicle distance is added into the information displayed by the head-up display, which is increased a lot of convenience for drivers. Besides, the external head-up displays in the market is various, and the prices are from several hundred dollars for simple function ones, to ten thousand dollars for good quality and versatile ones.
As above, the technique of the head-up displays has been widely used in the vehicles. The related patent references are numerous, the typical representative such as TW M425068 (called cited reference 1, as shown in FIG. 1), TW 1305757 (called cited reference 2, as shown in FIG. 2). Wherein, in the cited reference 1, which includes: at least an image capture unit 10, which is used to monitor the driving dynamics outside the car and generate at least a dynamic image; a head-up display unit 20, which includes an image projection module 21 for projecting images, and an image reflection module 22 covered on a front windshield of the car. The image reflection module 22 is used to reflect the light and shade, by the auxiliary of the light and shade, the driving dynamics may be monitored. The cited reference 1 has disclosed that multiple photography devices 11, 12, 13, 14 are used to shot the image outside the car and output the shot images to the head-up display unit 20. Although the cited reference 1 may capture images from many directions, the head-up display unit 20 may only displayed one of the shot images according to the driving conditions. For example, when the right direction indicator is started, a right side (or right rear) image is switched to be displayed through a switch circuit 15, this kind of single (or single side) image cannot really provides the panoramic image around the car to the driver timely, so there are still dead angles of drivers' line of sight.
In the cited reference 2 installed on a car, includes: a CMOS image capture device 31, which is installed in a specific position on a rear section of the car and used to capture a rear image for performing image processing to thereby output a corresponding image signal; at least a high-brightness LED 32, which is installed in a specific position on the rear section of the car near the bumper; a display unit 33, which is set inside the car; a controller 34, which is electrically connected to the CMOS image capture device 31, the at least a high-brightness LED 32 and the display unit 33, wherein the controller 34 is used to control the at least a high-brightness LED 32 to emit light, control the CMOS image capture device 31 to capture the rear image for performing image processing, and control the display unit 33 to display the rear image; and a starting device 30, which is electrically connected to the controller 34 and is used to output a starting signal to the controller 34, the controller retrieves the starting signal to control the at least a high-brightness LED 32 to emit light; the starting device 30 is consisted of any one of the following groups: (a) a reverse speed change device 35, and the starting signal is a reverse gear signal output by the reverse speed change device; (b) a photosensitive switch 36, and the starting signal is a low light signal output by the photosensitive switch; and (c) an electronic clock 37, and the starting signal is an alarm signal output by the electronic clock 37, which has disclosed that the photography lens is used to shot the rear image, and a high-brightness LED 32 is used to fill light to the image. The cited reference 2 could only provide the rear image, and for the dead angles of line of sight in the right side and the left side of the car, the driver still need to turn his head to see the left and right rearview mirrors for overcoming the dead angles of line of sight.